Oceanographic conditions in the southern bay of Bengal from ~0.8 - 1.3ma

• Main Author: Lagos, Alexandria Desirae
• Other Authors: Earth & Climate Sciences
• Format: Thesis
• Language: English
• Published: San Francisco State University 2019
• Subjects: Indian; Planktonic foraminifera
• Online Access: http://hdl.handle.net/10211.3/213684

IODP Expedition 354 drilled an east-west transect of 7 cores in the southern Bay of Bengal that are well situated for better understanding the link between the tropical Indian Ocean and the northern Bay of Bengal. We focus on IODP site U1452 (8 ??N, 87??E; 3670m water depth), where we reconstructed Mid-Pleistocene (0.84 - 1.27Ma) oceanographic conditions using the Mg/Ca and 8180 of the planktonic foraminifera, Globigerinoides Sacculifer, and the 8180 and 8 13C of the benthic foraminifera, Uvigerina peregrina. We used G. Sacculifer Mg/Ca to generate a sea surface temperature (SST) record ranging from 26.9 - 31.2??C during the Mid-Pleistocene. The mean SST remains stable at 28.9??C and has no long-term temperature trend from 0.84 - 1.27Ma. The 8180 of G. sacculifer calcite and SST records were used to estimate the 8180 of seawater (Bemis et al., 1998), which ranges from 0.7 - 2.2%o. The benthic U. peregrina 8180 record ranges from 3.2 - 4.7%o, which is consistent with LR04 benthic 8180 stack (3.2 - 4.7%o; Liseicki & Raymo, 2005). While the U. peregrina 8180 record captures the glacial cycles, the timing is offset from the LR04 stack, suggesting further fine-tuning of the IODP site U1452 age model may be needed. The benthic 8 13C record ranges from -1.9 to -0.9%o, with a ~0.3%o decrease in amplitude through the Mid-Pleistocene, a trend consistent with other deep-ocean 8 13C records.